/in/foo.cc: In function 'int main()':
/in/foo.cc:155:5: error: 'sort' was not declared in this scope; did you mean 'sqrt'?
  155 |     sort(rows.begin(), rows.end());
      |     ^~~~
      |     sqrt
/in/foo.cc:156:16: error: 'unique' was not declared in this scope
  156 |     rows.erase(unique(rows.begin(), rows.end()), rows.end());
      |                ^~~~~~